To be fair, the medical establishment did lie about it, but not because of some weird “big mask” or “big pharma” conspiracy, but because they have a tangible impact when used by large groups and overselling them would have better outcomes than underselling them.
It’s a classic problem those in power have to deal with: tell the truth and get an underwhelming response, or oversell and get a better response.
Don’t take horse dewormers though, that’s just dumb.